1: With hydrogenchloride; sodium nitrite in water T=0°C; 0.75 h; Inert atmosphere; 2: With potassium ethylxanthate in water T=75°C; 1 h; Inert atmosphere; 3: With potassium hydroxide in ethanol; water 17 h; RefluxInert atmosphere;

1.1: N-bromosuccinmide / 1.25 h / 20 °C / Inert atmosphere 2.1: hydrogenchloride; sodium nitrite / water / 0.75 h / 0 °C / Inert atmosphere 2.2: 1 h / 75 °C / Inert atmosphere 2.3: 17 h / Reflux; Inert atmosphere View Scheme

1: NaOEt / ethanol 2: SnCl2, aq. HCl 3: (cyclisation) 4: Py*HCl View Scheme

1: NaOEt / ethanol 2: SnCl2, aq. HCl 3: (cyclisation) 4: Py*HCl 5: K2CO3 / acetone 6: NaH / toluene / 10 h / Heating 7: aq. HCl / 0.5 h / Heating View Scheme